Anodic Oxidation of Nitrite at a Molybdenum Oxide Layer

Abstract

The anodic oxidation of nitrite at a glassy carbon surface modified by a molybdenum oxide layer electrochemically deposited is discussed. The results demonstrated that at certain thickness values the film is permeable to small substrates like iodide and nitrite. On the other hand, at anhydrous films (prepared by vacuum evaporation) no electrochemical response for nitrite was observed in experiments performed in a CH3CN solution, confirming the relationship between the porosity of the film and its water content. Voltammetric curves recorded in alkaline solutions showed an enhanced response for the oxidation of nitrite when the electrode surface is modified with the MoO3 film, which is nonconductive at the working potential range. The current enhancement is probably associated with an entrapment of NO2 (electrogenerated in a first step) at the electrode/film interface, the MoO3 sites transferring an O‐atom in a further step. The modified electrode was used as an amperometric sensor for nitrite in a flow injection configuration, the method being applicable in the range 5 to 1000 μM at a potential of 1.0 V. The repeatability of the analysis is around 3 % and the lower limit of detection is 1 μM. The method was used in the determination of nitrite in sausage samples with a recovery of 104 %.

Metallophthalocyanine-based molecular materials as catalysts for electrochemical reactions

“…In order to avoid such limitations, several studies have reported on the use of chemically modified electrodes with phthalocyanines, porphyrins, hemoglobin, and myoglobin for the reduction of nitrite [150,276,[441][442][443][444][445][446][447]. In spite of the fact that the anodic electrochemical determination of this anion offers several advantages, such as no interference from nitrate and from molecular oxygen, there are very few reports related to the oxidation of nitrite [277,448].…”

The use of a new twin-electrode thin-layer cell to the study of homogeneous processes coupled to electrode reactions

“…Obviously, this assumption is valid for reversible electrochemical systems such as the ferri/ferrocyanide couple, as previously demonstrated. On the other hand, nitrite is a well-studied anion whose irreversible anodic oxidation leads to nitrate in a 2-electron process [26], as Eq. (9) shows:…”

Electrocatalytic oxidation of nitrite by tetra-substituted oxotitanium(IV) phthalocyanines adsorbed or polymerised on glassy carbon electrode

“…However, use of electrochemical [8][9][10] methods is fast increasing as they are faster, safer and precise for the nitrite analysis. Nitrite oxidation is usually favoured over reduction since interferences such as nitrate and oxygen are avoided [11,12]. Poor sensitivity often results from the oxidation of nitrite at a bare electrode, since the surface is passivated by species that may be generated in solution due to high overpotentials.…”

“…Tau, T. Nyokong / Journal of Electroanalytical Chemistry 611 (2007)[10][11][12][13][14][15][16][17][18] …”